Silly Putty is a toy containing silicone polymers that have unusual physical properties. It can flow like a liquid, bounce and can be stretched or broken depending on the amount of physical stress to which it is subjected. It contains viscoelastic liquid silicones, a type of non-Newtonian fluid, which makes it act as a viscous liquid over a long period of time but as an elastic solid over a short time period. It was originally created during research into a potential rubber substitute for use by the United States in World War II.[1][2][3]
The name Silly Putty is a trademark of Crayola LLC.[4] Other names are used to market similar substances from other manufacturers.